I made the forgotten cookies in the evening, preheating the oven as instructed and turning it off as soon as the tray was in the oven. The mixture made exactly 12 round balls but when I opened the oven this morning, they had spread a bit and were much flatter than in the photo. What did I do wrong - whipped too much? Not enough?
Nigella's Forgotten Cookies (from AT MY TABLE) are meringues that are put into a hot oven. The oven is then turned off and the meringues cook slowly in the cooling oven. The meringues should keep their shape, so if they are spreading then it is likely that the meringue was not whisked properly and there are several possible reasons.
First ensure that your egg whites do not contain any specks of yolk and the bowl and beaters are completely grease-free. Particularly if you use a plastic bowl as plastic tends to cling on to traces of grease. It can help to wipe the bowl and beaters with a paper towel dipped in lemon juice before you start making the cookies. Make sure that the whites are properly at soft peaks before adding the sugar - when you lift the beaters the whisked whites should form a peak with a flopped over top. Whisk the whites starting with a low speed and moving up to a medium speed, until soft peaks are reached, as starting straightaway on high speed can lead to uneven air bubbles and the larger ones can burst easily, causing the meringue to spread. Also make sure that you use caster or superfine sugar and that each addition of sugar is whisked in properly before adding the next, as if the sugar is not properly dissolved it can seep out in baking and could make the meringues a little flat.